Method, apparatus and arrangement in a telecommunications network for providing control over and enabling advanced services and user interfaces in a mobile telephone

ABSTRACT

A PBX ( 10 ) is connected to a mobile telephony network ( 40 ) via a PSTN ( 20 ) and via a LAN ( 90 ) and data network ( 30 ). A mobile telephone ( 50 ) served by the mobile network, has a separate data channel ( 100 ). The invention describes a way to integrate mobile telephones as extensions of the PBX and to provide them with functionality similar to that of a wired digital PBX system telephone ( 70 ). The data channel of the mobile telephone is used to give the PBX access to the user interface devices of the telephone. The speech path between the PBX and the mobile telephone may be set up in the direction from the PBX to the mobile telephone, even when the call was initiated at the telephone. The invention relies only on the basic voice and data communications services of the mobile telephony network, and therefore provides independence from the network operator.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to apparatuses, methods and arrangementsin a telecommunications network, including a mobile telephony network,for providing control over and enabling advanced services and userinterfaces in a mobile telephone.

DESCRIPTION OF RELATED ART

The telephony services provided today by a mobile telephony network tomobile telephones are, apart from the mobility itself, typically similarto those provided by the PSTN to fixed extensions. A private branchexchange (PBX) typically relates to mobile telephones in much the sameway as it relates to fixed extensions in the PSTN.

EP0865219 (Björk) teaches a base station subsystem that via a mobilityserver is connected to a PBX and to a public network. With Björk'ssolution, the advanced telephony services of the PBX cannot be providedto mobile telephones located outside of the coverage of the base stationsubsystem, which is typically the PBX owner's premises. Björk's solutionrequires very close cooperation with a network operator.

WO 0119093 (Wallenius) teaches using WAP for call control in anintelligent network. Wallenius' solution is intended to be a part of thenetwork, or is at least dependent on very close cooperation with thenetwork operator.

WO0065862 (Fils) teaches using a separate communications path to handlesignalling for call redirection. Fils solution is intended to be a partof the network, or is at at least dependent on very close cooperationwith the network operator.

SUMMARY OF THE INVENTION

A PBX (Private branch exchange) provides advanced telephony services anduser interfaces to its users, and gives good control of call handlingand of telephony costs.

Telephony users are becoming more mobile, often using mobile telephonesto work at home or on the move. However, as the mobile telephones arenot extensions of a PBX, the advantages of the PBX are lost. The presentinvention is concerned with the problem of integrating mobile telephonesas extensions of a PBX.

A first problem in achieving integration is that the mobile telephone isnot registered as an extension in the PBX.

A second problem is that the PBX does not have access to the userinterface devices of the mobile telephone, and therefore cannot providethe advanced user interface of the PBX to the user of the mobiletelephone.

Another problem is that the PBX does not control the setup of speechchannel from the mobile telephone to the PBX

A related problem is that the PBX needs signalling access to the mobiletelephone, so that call-related signalling can be exchanged freelybetween the PBX and the mobile telephone.

A problem with signalling access is that network operator policies maylimit the way that available signalling schemes in the mobile telephonynetwork and public telephone network signalling channels may be used byother parties such as PBX:s.

Another problem with signalling access is that signalling through themobile telephony network and public telephone network signallingchannels does not provide all the functionality needed for advancedtelephony services and user interfaces. It is unlikely that networkoperators would be willing to implement additions to their signallingservices to satisfy the owner of a PBX who wants to have mobiletelephones as extensions.

A further problem is that outgoing calls from the mobile telephone arerouted and handled according to the choice of the mobile networkoperator. The owner of a PBX may want the outgoing calls from the mobiletelephone to be connected via the PBX, so that a choice can be made ofwhich operators to use, or otherwise to have better control over callhandling. This would require an agreement with the operator thatoutgoing calls from the mobile telephone always be routed to the PBX,since the routing of outgoing calls is controlled by the operator.

Another problem is that text-based directory lookup services for mobiletelephones using standard browsers cannot easily be integrated with callsetup. When the sought number is found, the user must manually enter thenumber on the keypad of the mobile telephone.

The problems are solved by the following:

In order to integrate the mobile telephone as an extension of the PBX,it is registered as an extension in the PBX.

Further, the PBX is given control of the user interface devices of themobile telephone by the PBX communicating (exchanging messages,signalling) with software in the mobile telephone.

To give the PBX free signalling access to the mobile telephone, aseparate data channel is used instead of the normal channel forcall-related signalling.

To give the PBX control over speech channel setup, and to give bettercontrol over call handling and costs, all calls through the mobiletelephony network (including those initiated at the mobile telephone)are set up in the direction from the PBX to the mobile telephone.

To save a mobile user of a text-based directory lookup service fromhaving to enter a found number manually on the mobile telephone keypad,a “Call” alternative is provided in the lookup service. When thealternative is selected, the PBX sets up the call.

More closely, the abovementioned problems are solved as follows.

The mobile telephone is assigned an extension identity in the PBX. Sincethe PBX is independent from the mobile telephony network, the identityneed not correspond in any way to the identity of the mobile telephonein the mobile telephony network, but can, for example, be a number muchshorter than ordinary mobile telephone numbers, as is typical for PBXextension numbers.

The extension identity is stored in the PBX along with other extensiondata as needed to provide advanced telephony services and userinterfaces and give control of call handling and costs.

The mobile telephone is provided with software with which the PBX cancommunicate to control the user interface devices and calling functionsof the mobile telephone.

The mobile telephone has, in addition to the normal speech andsignalling channels used for calls, a separate data channel forcommunication via a data network. This channel is used for the exchangeof messages (signalling) between the PBX and the software in the-mobiletelephone, since the signalling on this channel is free fromrestrictions by operator policies and limited functionality.

The ordinary signalling channel is used only for basic signallingbetween the mobile telephone and the mobile telephony network.

All calls through the mobile telephony network are set up in thedirection from the PBX to the mobile telephone. When the mobiletelephone user wants to make a call, this is signalled to the PBX on theseparate data channel, instead of to the mobile network on the ordinarysignalling channel. The PBX then sets up a call from the PBX to themobile telephone and another call from the PBX to the desireddestination. The two calls are connected to each other.

In the text-based directory lookup service, when a number has beenfound, a “call” alternative is provided. When this alternative isselected, information that the selection has taken place is transferredover the separate data channel to the directory service, which forwardsit to the PBX, and a call is set up in the direction from the PBX to themobile telephone and from the PBX to the destination, as describedabove.

It is an object of the present invention to integrate mobile telephonesas extensions in a PBX in a way that makes it possible to provideadvanced telephony services and user interfaces and give good control ofcall handling and cost.

It is an object of the present invention to acheive the integrationusing only the basic telephony and data communication services of themobile telephony network, and not require any special interfaces withthe mobile network or special agreements with its operator, therebygaining independence from the operator.

It is an object of the present invention to give the PBX control of theuser interface devices and calling functions of the mobile telephone, sothat the advanced user interface of a PBX extension can be provided tothe user of the mobile telephone.

It is an object of the present invention to provide unrestrictedsignalling access between the PBX and the mobile telephone.

It is an object of the present invention to give the PBX owner bettercontrol of the setup, routing and other handling of calls from mobiletelephones, independent of the operator of the mobile telephony network.

It is an object of the present invention to save the user from having tomanually enter a number found in a text-based directory lookup servicein order to set up a call to it.

An advantage of the present invention is thus that the PBX hasunrestricted access to the mobile telephone for call-related signalling.

Another advantage is that the PBX can control the user interface devicesand calling functions of the mobile telephone and provide an advanceduser interface.

Another advantage of the present invention is that mobile telephones canbe integrated as extensions in a PBX and provided with advancedtelephony services and user interfaces and which will give good controlof call handling and cost.

A further advantage is that said integration can be acheived using onlythe basic telephony and data communications services of the mobiletelephony network, without relying on special interfaces or specialagreements.

Still an advantage is that the PBX owner can better control the setup,routing and other handling of calls from mobile telephones, independentof the operator.

Another advantage is that telephony support applications such asdirectory lookup can be integrated with call setup.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described in connection withfigures, of which:

FIG. 1 shows a block schematic of a telecommunications network.

FIG. 2 shows a block schematic of an alternative telecommunicationsnetwork.

FIG. 3 shows a flow diagram of setting up of an incoming call to amobile telephone.

FIG. 4 shows a flow diagram of setting up of an outgoing call from amobile telephone.

FIG. 5 shows a flow diagram of a mobile telephone ending a call.

FIG. 6 shows a flow diagram of an alternative way of a mobile telephoneending a call.

FIG. 7 shows a flow diagram of a mobile telephone setting up a call to anumber found through a directory search.

DETAILED DESCRIPTION OF EMBODIMENTS

With reference to FIG. 1, the invention comprises a PBX 10, a publictelephone network (PSTN) 20, a local area network (LAN)90, a datanetwork 30, a mobile telephony network 40 and a mobile telephone 50.

The mobile telephony network 40 connects to other fixed networks such asthe PSTN 20 and the data network 30 at an interface to fixed networks41. Interface 41 may comprise multiple, distributed logical and physicalinterfaces.

The PBX 10 is typically a single entity, but may also be composed of anumber of servers under common administration that share a common set ofextension identities and collaborate to handle calls to and from theseextensions (not shown).

The PBX 10 is connected to the PSTN 20 via a trunk interface 320. Theinterface 320 is a public network trunk access interface, for examplethe ISDN T reference point.

The PBX 10 may have ordinary wired extensions, analog 60 or digital 70,connected through line interfaces 330 and 340. It can also have IPextensions 80 connected over a LAN or other IP data network 95. Thenetworks 90 and 95 are connected to the PBX via data network interfaces310 and 315. In an alternative, a single network is used.

The PBX has one or more conference devices 400, which are used toconnect several extensions in a conference call.

The digital extensions 70 and IP extensions 80 are normally equippedwith a display and a keyboard with more keys than a conventional analogtelephone 60.

The PBX normally presents menus of service alternatives on the displayof the digital extension 70 or IP extension 80. The menu alternativesare adapted to be relevant to the current calling status (state), e.g.if a called extension is busy, the caller's menu includes the call backservice. A change state of the extension or of a call on it may thuslead to a change of menu. Also calling line identification informationis displayed, as well as call progress information. The extensions mayhave many buttons in addition to the usual 0-9, # and *. These buttonsmay function to invoke services. The function of some buttons may bechanged according to the current call status to provide relevantservices, and the current meaning of a button may be displayed on thedisplay. This presents an advanced and user friendly user interface.

The PBX 10 can set up normal telephone calls to the mobile telephone 50via the trunk 25, the PSTN 20 and the mobile telephony network 40. Thisis governed by signalling between the PBX and the PSTN on the signallingchannel 140, by signalling between the PSTN and the mobile telephonynetwork on the signalling channel 130, and by signalling between themobile telephony network and the mobile telephone on the signallingchannel 110. A speech channel 120 is set up from the PBX to the mobiletelephone when the call is connected.

In an alternative, the PBX has a dedicated connection to the mobiletelephony network instead of the PSTN. However, the PSTN may be neededanyway for other communication between the PBX and destinations in thePSTN, and is then connected with another trunk interface 321 and anothertrunk 26, as shown in FIG. 2.

In another alternative, the PBX 10 can set up calls to the mobiletelephone 50 via a trunk connection to another telephone exchange thatis connected to the PSTN 20 (not shown).

The functionalities of the signalling channels 140 in the PSTN and 110to the mobile telephone are controlled by the operators of the PSTN 20and the mobile telephony network 40 respectively, and normally do notprovide the functionality needed for advanced telephony services anduser interfaces. The signalling path through signalling channel 110,mobile telephony network 40, signalling channel 130, PSTN 20 andsignalling channel 140 can not be used to give the PBX 10 control of theuser interface devices of mobile telephone 50.

The mobile telephone 50 has a display and a keyboard. It also has thecapability to emit alerting sounds, e.g. to sound a ring signal.

The mobile telephone 50 may be a conventional mobile telephone, or itmay be some other device comprising mobile telephone functionality, forexample a PDA (Personal Digital Assistant) with mobile telephonefunctionality.

The mobile telephone 50 and the mobile telephony network 40 support adata communication service, such as GPRS or the data communicationservice of UMTS. Thus the mobile telephone 50 has a separate datachannel 100 for data communication with a data network 30.

The data network 30 and the LAN 90 connect the PBX 10 to the datacommunications service of the mobile telephony network 40. The LAN isconnected at a data communications interface 310 of the PBX. The PBX andthe mobile telephone can exchange messages via the data channel 100, thedata network 30 and the LAN 90. This signalling path does not have thelimitations of the signalling path 110-40-130-20-140 through the PSTN,described above. Instead, messages are delivered end-to-end regardlessof content. Thus, the PBX 10 can use this path to control of the userinterface devices of the mobile telephone 50.

In an alternative, the PBX via an interface 311 has a dedicated dataconnection 31 to the mobile telephony network, instead of the datanetwork 30 as shown in FIG. 2.

In another alternative, the PBX does not exchange messages directly withthe mobile telephone, but via an intervening server 200, that may be aWAP server. The server may handle communication protocols, addformatting and user interface details to messages or otherwise convertthe format of exchanged messages. The server may adapt the communicationto suit a browser in the mobile telephone 50.

The server may communicate with a CSTA (Computer Supported TelephonyApplications) interface of the PBX 10. The CSTA interface may be asoftware entity, reached through the LAN interface 310. Alternatively,the CSTA interface may be provided by a CSTA server (not shown) thatcommunicates with the PBX.

In a further alternative, a text-based directory lookup service isprovided by a server 210. The server is connected to the LAN 90 andthereby has connectivity to the PBX 10 and the data network 30. In analternative, the server 210 has dedicated connections (not shown) to thedata network 30 and the PBX 10. The server 210 may communicate with thePBX 10 through the CSTA interface (not shown) of the PBX.

The directory lookup service communicates with the mobile telephoneeither directly or through the server 200 that may be a WAP server. Theservice lets a user of the mobile telephone 50 find data about otherusers of the PBX, such as their extension numbers and mail addresses.

In order to integrate the mobile telephone 50 as an extension in the PBX10, the mobile telephone is assigned an extension identity in the PBX.This is often a number of from 2 to 5 digits. There need not be anycorrespondence between the extension number, and the telephone number orother identity of the mobile telephone in the mobile telephony network.

The PBX 10 also stores data about the extension. The stored datacomprises information about the number of the mobile telephone in themobile telephony network and information on where to adress messages forthe mobile telephone that are to be sent on the data channel. It alsocomprises information about the rights of the extension user to make useof PBX resources, such as whether she is allowed to make internationalcalls, and information about user settings and preferences, such asdiversion options, etc. The information about rights, settings andpreferences is selectable independent from the operators of the mobiletelephony network 40 and the PSTN 20. The PBX 10 also keeps informationabout the current status of the extension, such as if it is busy oridle.

The mobile telephone 50 is equipped with software that allows the PBX 10to present information on the screen of the mobile telephone by sendingmessages (signals) to it over the data channel 100. The software alsoallows the user of the mobile telephone 50 to provide input to thekeyboard or other input device of the mobile telephone, whereby the PBX10 is informed of the user input through a message sent from the mobiletelephone 50 to the PBX 10 over the data channel 100.

The software may also allow the PBX 10 to cause the mobile telephone 50to emit a sound, for example to signal an incoming call, and it mayallow the PBX 10 to cause the mobile telephone 50 to send an answermessage to the mobile telephony network on the ordinary signallingchannel 110, or even provide the PBX with complete control of theordinary calling functions of the mobile telephone. Alternatively, themobile telephone 50 may be configured to answer incoming callsautomatically.

The software in the mobile telephone may be specially written for thepresent invention, or it may consist of a WAP browser that communicateswith the PBX via a WAP server, or some other suitable browser, or it maybe a combination of a standard browser and specially made enhancementsand adaptions.

When the PBX 10 has the ability to communicate with the user interfacedevices of the mobile telephone 50, the setup of speech path between thePBX and the mobile telephone can be controlled by the PBX, since allcalls can be setup in the direction from the PBX to the mobiletelephone, or the PBX may cause the mobile telephone to set up a call tothe PBX.

In the way described above, by using the data channel 100 forunrestricted communication between the PBX and the, mobile telephone, bygiving the PBX 10 control over the display and other output from themobile telephone 50, by providing to the PBX information about userinput on the mobile telephone 50, and by the PBX 10 being able tocontrol the setup of a speech channel between the PBX and the mobiletelephone, the services of the PBX 10 can be provided to the mobiletelephone 50 with the same functionality as for a wired PBX digitalsystem telephone 70.

Specifically, the PBX can display menues of service alternatives to theuser of mobile telephone 50, and the menues can be changed in the courseof making calls or otherwise using the phone, so that the menu alwayspresents services or alternatives that are especially relevant to whatthe user currently is doing, e.g. present a “call back” alternative whenthe user has made a call and encountered busy, or a “conference”alternative when the user has a party parked and makes an inquiry to athird party.

The same set of services that is available to a wired digital systemtelephone 70 will be available to the mobile telephone 50. This includesservices such as conference call, park/inquiry, operator camp-on,diversion and follow-me, as well as administrative functions of the PBX,such as logging of calls, setting of restrictions on outgoing calls on aper-user basis, etc. A list of some typical PBX services is provided inappendix A.

Apart from the basic subscription for telephony and data communicationsservice, which is part of the mobile operator's normal service offering,there is no need for a special agreement with the mobile operator. Thereis also no need for special interfaces to the mobile network apart fromthose which are normally used to access the basic services. Thisprovides independence from the operator, which is a particular advantagein situations where mobile operators are unwilling, or even hostile toattempts by other parties to provide advanced services to mobiletelephones.

A modern PBX typically provides over 500 different telephony services.Specific examples will be given below for a few of those services.

Incoming Call

With reference to FIG. 3, an incoming call to the mobile telephone 50 ishandled as follows.

Extension 1234 is a wired digital PBX system telephone 70, belonging touser Jim Smith. The mobile telephone 50 belongs to user John Doe and hasextension number 5678.

In a step 501, Jim Smith dials 5678 to call John Doe. In a step 502, thePBX checks the status of extension 5678. If it is busy, alternative“Yes” in a step 503, Jim Smith receives busy tone in the conventionalway, step 540.

If extension 5678 is not busy, the PBX 10 proceeds with call setup. Twosequences of events, namely steps 510 through 513 and steps 520 through523 now occur in parallel.

In the step 520, the PBX initiates, by signalling on the ordinarysignalling channel 140, an ordinary external call through the PSTN 20and the mobile network 40 to the mobile telephone 50.

In a step 521, the mobile telephone receives an indication of theincoming call in the ordinary way over signalling channel 110.

In a step 522, the mobile telephone automatically sends an answerindication to the mobile telephony network on the ordinary signallingchannel 110, as soon as it has received the indication of the incomingcall from the mobile telephony network (autoanswer).

When the mobile telephony network 40 receives the answer indication overthe ordinary signalling channel 110, a speech path is set up from thePBX 10 to the mobile telephone 50 in the ordinary way, step 523.

At the same time as the ordinary call is initiated, the PBX 10 sends tothe mobile telephone 50 over the data channel 100 a first messageindicating the incoming call from Jim Smith, step 510.

The first message may include the extension number and name of thecalling party (1234 Jim Smith), to be displayed on the display of mobiletelephone 50, as well as relevant service alternatives.

This is a particular advantage over a traditional call from a PBXextension over the PSTN and mobile telephony network to a mobileextension. Often only the external number of the PBX switchboard isshown as calling line identification (CLI) if an extension calls amobile telephone, or if an external party calls into an extension thatis diverted to a mobile telephone. That is not very informative.

When the first message indicating the incoming call has been receivedover the data channel 100, the number and name of the calling party(1234 Jim Smith) is displayed on the mobile telephone along with servicealternatives such as “answer”, “reject”, “divert to voicemail”, etc,step 511.

When the user John Doe of the mobile telephone 50 selects “answer”, step512, the PBX 10 is informed of this fact through communication over thedata channel 100, step 513.

When steps 513 and 523 have been completed, the PBX 10 extends theestablished speech connection with mobile telephone 50 to the telephone70 of extension 1234, and the call between Jim Smith and John Doe hasthus been set up, step 530.

In an alternative, instead of the mobile telephone 50 automaticallysending an answer indication over the ordinary signalling channel 110,the PBX 10 may send a second message on the data channel 100 causing themobile telephone to send an answer indication to the mobile telephonynetwork on the ordinary signalling channel 110. The PBX may wait untilit has received information that John Doe has selected to answer thecall before it sends the message over the data channel 100 that causesthe mobile telephone 50 to send the answer indication on the signallingchannel 110, or it may be sent as soon as the PBX receives an “alerting”indication on the signalling channel 140.

In another alternative, the ordinary call through the PSTN may beinitiated only after user John Doe of the mobile telephone 50 hasselected to answer the call from Jim Smith, that is, step 520 is carriedout after step 513 has been completed and the PBX has receivedinformation that John Doe has selected to answer.

In a further alternative, John Doe may have to press the normal answerbutton of the mobile telephone 50 to send the answer indication to themobile telephony network over the ordinary signalling channel 110. Inyet an alternative, the mobile telephone 50 sends the answer indicationover the channel 110 when John Doe selects the “Answer” alternative inresponse to the incoming call from John Smith.

In still an alternative, the ordinary call through the PSTN is set upbefore any indication of the incoming call is sent over the data channel100, that is, step 510 is not carried out until step 523 has beencompleted.

Outgoing Call

John Doe decides to call Jim Smith. As before, John Doe is the user ofmobile telephone 50 which has extension number 5678, and Jim Smith isthe user of wired telephone 70 which has extension number 1234. Withreference to FIG. 4, the following events take place.

In a step 601, John enters the number 1234 on the mobile telephonekeypad, and selects “Call”. This may be by pressing a specific button,or by selecting an alternative presented on the screen.

The mobile telephone 50 sends to the PBX 10 over the data channel 100the information that the user has selected to call the number 1234, step602. Alternatively, the PBX is separately informed of each buttonpressed on the mobile telephone, and from this information concludesthat the user has selected to call extension 1234.

The PBX receives the information that the user of mobile telephone 50wants to call extension 1234 and proceeds to check the status ofextension 1234, step 603.

If the extension 1234 is busy, alternative “Yes” in a step 604, nospeech paths are set up, instead the PBX sends a message back to themobile telephone over the data channel 100 causing it displayinformation about this fact, along with relevant service alternativessuch as “Call Back”, “Connect to Voicemail” or “Connect to operator”,step 610.

If John selects call back, step 611, this is communicated to the PBX 10over the data channel 100, step 612, and the PBX activates the callbackservice, step 613.

If extension 1234 is not busy, alternative “No” in the step 604, the PBX10 proceeds to set up a speech path to extension 1234 in the normal way,step 620, and also sets up an ordinary outgoing external call from thePBX to mobile telephone 50, step 621. The mobile telephone 50 answersthe call automatically, step 622, or else the PBX causes it to answer bysending it a message. Alternatively, the user may have to press ananswer button on the mobile telephone. A speech channel 120 between thePBX and the mobile telephone is established, step 623.

The PBX 10 causes extension 1234 to ring, and ringing tone is sent tomobile telephone 50 over the established speech channel 120, step 624.

While the call is being set up, the PBX may present service alternativeson the display of the mobile telephone, such as “Call Back”, step 625.If Jim Smith does not answer and John Doe selects “Call Back”,alternative “Yes” in a step 626, the PBX 10 is informed of the selectionthrough a message over the data channel 100, step 630, call setup isaborted, step 631, and the callback service is activated, step 632.

If instead extension 1234 answers, step 640, the speech paths areconnected, to form a speech connection between mobile telephone 50 andextension 1234, and the call from John Doe to Jim Smith has thus beenset up, step 641.

In an alternative, the speech connection 120 is set up in the directionfrom the mobile telephone 50 to the PBX, instead of the other wayaround. The PBX may send a message to the mobile telephone over the datachannel 100, causing it to initiate a call from the mobile telephonethrough the mobile telephony network to the PBX, Except for the reverseddirection of setting up the speech channel 120, the call is handled asdescribed above.

In a further alternative, the software in the mobile telephone 50detects that the user wants to make a call and sets up a call to the PBXwithout the PBX having to send a message for that purpose.

Outgoing Call to External Destination

An external destination is one which is not an extension of the PBX 10.It is typically reached through the PSTN 20.

An outgoing call from the mobile telephone 50 to an external destinationis handled similar to the call described above to extension 1234. Whenthe destination is external, the PBX 10 checks the rights of John Doe atextension 5678 to make an external call, and if he is not allowed tocall the desired destination, the call is rejected and no speech pathsare set up. If the call is allowed, a first ordinary, outgoing externalcall is set up to mobile telephone 50 as described above, and a secondordinary outgoing external call is set up to the desired destination,instead of the call setup towards extension 1234. When the desireddestination answers, the speech path of the second ordinary outgoingcall is connected to the speech path of the first ordinary outgoingexternal call from PBX 10 to mobile telephone 50, to form a speech pathfrom the mobile telephone to the desired destination.

A particular advantage when setting up ordinary outgoing external callsfrom the PBX is that the PBX can control which operator to use for thecall. When an ordinary call is set up from mobile telephone 50 throughmobile telephony network 40, it is the operator of network 40 thatdecides which operator to use for the further connection of the calloutside of the mobile network 40.

“Call” Alternative in Directory Service.

When the user of the mobile telephone 50 is making use of a text-baseddirectory lookup service, provided by the server 210 and accessed viathe data channel 100, it is inconvenient to enter a found destinationnumber on the keyboard of the mobile telephone. Therefore, the menu ofthe directory service is provided with a “call” alternative. When thecall alternative is selected, the directory service signals this to thePBX. The PBX then sets up the call as described above. Specifically, thespeech path between the PBX and the mobile telephone may be setup by wayof an ordinary outgoing call from the PBX to the mobile telephone.

In an alternative, the directory service uses the PBX CSTA interface toset up a call between the mobile telephone and the desired destination.

In another alternative the communication between directory server 210and mobile telephone 50 takes place via a server that may be the server200. The server 200 may be a WAP server. The server may handlecommunication protocols, add formatting and user interface details tomessages or otherwise convert the format of exchanged messages. This maybe done to suit a browser in the mobile telephone 50.

In a further alternative, the information that the user of mobiletelephone 50 has selected to call the found number is sent directly tothe PBX 10.

With reference to FIG. 7, a search and call may take place as follows.

In a step 901, the user of the mobile telephone 60 inputs searchcriteria to find a user in the directory service. In a step 902, thecriteria are sent to the directory service over the data channel 100.The directory service finds the number of the sought user, step 903 andsends the search results back to the mobile telephone over the datachannel 100, step 904. The mobile telephone displays the results, step905, along with service alternatives such as “Call”. In a step 906, theuser of the mobile telephone selects the “Call” alternative, and in astep 907, the directory service is informed of the selection through amessage over the data channel 100. In a step 908, the directory serviceorders the PBX to set up a call between the mobile telephone 50 and thenumber that was found in the directory search.

Outgoing Call from Browsing Call Log

PBX extensions are often equipped with a log of missed calls. Accordingto the present invention, the log can be accessed from the mobiletelephone 50 via communication with the PBX 10 over the data channel 100and missed calls can be displayed on the mobile telephone display.

Similar to the directory lookup service, a “Call” alternative isprovided, so that the user of the mobile telephone 50 can select amissed call and then select to call the party that the missed call wasfrom. The information that the user has selected to call the party thatoriginated the missed call is then transfered to the PBX over the datachannel 100 and a call is set up as described above. Specifically, thespeech path between the PBX and the mobile telephone may be set up byway of an ordinary outgoing call from the PBX to the mobile telephone.

Inquiry and Conference

During an ongoing call, the PBX may present service alternatives on thedisplay of the mobile telephone 50 by sending information to the mobiletelephone over the data channel 100.

One of these service alternatives may be the well-known “inquiry”service. When the user of the mobile telephone selects to make aninquiry to another extension or external number, this is communicated tothe PBX 10 over the data channel 100. The PBX puts the line with whichthe mobile telephone is currently connected on hold and sets up a newcall to the destination of the inquiry.

When the call to the inquired party has been answered, the servicealternatives displayed on the mobile telephone may include Conferencecall. If the alternative is selected, the selection is againcommunicated to the PBX over data channel 100, and the call from the PBXto the mobile telephone, the call to the inquired party and the call toextension 1234 are all connected to ports on the conference device 400,so that they may all speak to each other together.

Hanging Up from the Mobile Telephone.

With reference to FIG. 5, when the user of the mobile telephone 50selects to end the call, step 701, this is signalled to the PBX 10 overthe data channel 100, step 702, and the PBX then disconnects the call,step 703.

In an alternative, with reference to FIG. 6, the user of mobiletelephone 50 presses a hangup button, step 801, that activates theordinary hangup function of the mobile telephone, and the mobiletelephone signals to the mobile telephony network 40 over the ordinarysignalling channel 110 that the call is to be disconnected, step 802.The PBX receives information of the disconnection on the ordinarysignalling channel 140, step 803, and subsequently disconnects anyremaining speech paths and other resources belonging to the call, step804.

After the call has been disconnected, the PBX through communication onthe data channel 100, may cause the mobile telephone 50 to displayalternatives relevant to the current idle state of the telephone, suchas “Call” and “Divert”.

Message Waiting. “Listen” Alternative

When someone leaves a voice message or other message in the PBX forextension 5678, which is the mobile telephone 50, the PBX sends amessage to the mobile telephone over the data channel 100 to cause it todisplay a message waiting indication. If the message is a voice message,a “listen” alternative is provided. When the user selects the “listen”alternative, this is communicated to the PBX via the data channel 100,and a call to the voice mail facility of the PBX is set up so that theuser can listen to the message.

By communication over the data channel 100, the voice mail facility maycause alternatives for browsing, listening to and managing messages tobe displayed on the mobile telephone, to provide a convenient userinterface.

In an alternative, the selection to listen to a message is communicatedto the voice mail facility, and the voice mail facility then orders thePBX to set up a call between the mobile telephone and the voice mailfacility. The speech path between the PBX and the mobile telephone isset up similar to what is described above under “outgoing call”, forexample by way of an ordinary outgoing call from the PBX to the mobiletelephone.

Setting Preferences

There are a number of preferences and other settings associated with atypical modern PBX extension. For example, diversion, personal numberprofile and security lock.

These settings are conveniently accessed through the mobile telephoneinterface, through communication over the data channel 100.

Initialization

It is necessary for the PBX 10 to have information about what datanetwork adress to use to send messages intended to reach the mobiletelephone 50 over the data channel 100.

This information can be sent to the PBX 10 by the mobile telephone whenit is turned on. To do this, the mobile telephone has stored an addressof the PBX 10 to use when sending messages to it.

Alternatively, the mobile telephone can set up a session with the server200, that may be a WAP server. The server informs the PBX 10 of thesession identity and the PBX can then cause messages to be sent to themobile telephone by interacting with the server session.

The mobile telephone might retrieve the address of the PBX from anotherserver. The address of that server must then be stored in the mobiletelephone.

If the mobile telephony network provides a service whereby the datanetwork address of the mobile telephone can be provided if the telephonenumber of the mobile telephone is known, that service can be used by thePBX 10.

If the mobile telephony network provides fixed data network addressesfor mobile telephones, the fixed address of the mobile telephone may bestored permanently in the PBX.

Mobile Telephone Software

It may be desirable to use standard software in the mobile telephone 50,since otherwise software may have to be specially developed for thepurpose of the present invention.

However, standard browsers may not have all the needed functionality.For example, it may not be possible for the PBX to cause the mobiletelephone to emit a sound, or to control the calling functions of themobile telephone. The display of the mobile telephone may be overwrittenby the telephone standard software in the course of a call, so that thePBX cannot reliably use it to present alternatives tailored to theparticular call states. Information that is delivered to the browserusing WAP push functionality may not be presented directly on thedisplay as desired.

The limitations may be overcome by enhancing or adapting existingbrowsers to provide the needed functionality. A compromise can also bemade, sacrificing some functionality. For example, the normal ringsignal function of the mobile telephone may be used instead of aPBX-controlled one, and the user may have to use the normal answerbutton on the telephone, instead of the PBX causing the mobile telephoneto send an answer indication to the mobile telephony network, or thetelephone answering automatically. In that case, the phone would ring onboth incoming and outgoing calls, and the user would have to press thenormal answer button for the call to be connected. Likewise, the normalbutton for hanging up a call could be used, instead of PBX-controlledhangup.

If software is specially made, it may be designed to inform the PBX ofeach button pressed or other input from the user, so that the PBX mayuse this information to draw conclusions about user selections. Thedisplay of the mobile telephone may be updated by the PBX each time itreceives information that a button has been pressed, for example whenscrolling a list. This provides flexibility, in that the interfacepresented to the user may be changed by changing software in the PBX,but leads to increased communication over the data channel and possiblyto slower response to user input.

Alternatively, the handling of menus and selections may take place inthe software of the mobile telephone, so that the PBX need only sendinformation to the telephone when a new menu is to be presented, and thetelephone need not inform the PBX of every button pressed, but only whena selection has been made.

Mobile Telephones with Limited Data Channel

In some mobile telephones, the data channel 100 cannot be usedsimultaneously with the speech channel 120, for example in certainclasses of GPRS telephones. An incoming ordinary call may cause the datachannel to become unavailable.

If the mobile telephone 50 has such a limitation, it may be necessary toset up the speech channel as late as possible when setting up a call.

For example, in the setup of an incoming call as described in FIG. 3,the sequence of steps 510 through 513 should be carried out before thesequence of steps 520 through 523. Alternatively, the call could beanswered in the ordinary way by use of the answer button and an answerindication sent to the mobile network over the signalling channel 110,and only information about the caller being sent from the PBX 10 overthe data channel 100.

Some mobile telephone software would overwrite the caller informationdisplayed by the PBX with caller information supplied by the mobilenetwork 40 when the indication of the incoming call reaches the mobiletelephone over signalling channel 110. Such software needs to beadapted, or else the caller information supplied from the PBX will onlybe displayed for a short time.

When the speech channel 120 has been set up, interaction with the PBXvia the data channel 100 is not possible. During this time, in-band DTMFsignalling may be used to activate PBX services, for example pressing“5” to activate call-back towards an extension that does not answer, orpressing “3” to form a conference call from an onging call and a parkedparty.

All-IP Solution

To acheive complete independence from the call setup services of themobile telephony network 40, the data channel 100 may also be used totransfer speech. The mobile telephone 50 would be, equipped with thesame functionality as a wired IP extension 80 of the PBX, but instead ofthe wired IP connection, the data channel 100 is used for IPconnectivity. In this way, the call setup functions of the mobiletelephony network 40 need not be used at all. All calling communication,control signalling as well as speech, is handled solely on the datachannel 100.

Appendix A

List of some typical PBX services provided by the Ericsson MD110 PBX.

-   Direct indialling-   Inquiry and refer back-   Transfer-   Call waiting-   Conference-   Call back on busy-   Call back on free on no reply-   Executive intrusion-   Last external number redial-   Diversion by pass-   Abbreviated dialling common numbers-   Abbreviated dialling individual numbers-   Group call pick up-   Common bell group-   Individual call pick up-   Group hunting-   Paging-   Message waiting-   Diversion-   Follow Me-   General Cancellation-   Individual call charging-   Night service-   Emergency category-   Emergency extension-   Hot line-   Delayed Hot line-   Automatic answer category-   Authorization code-   Regional Authorization code-   Day and night categories for TCD-   Individual do not disturb-   Account code-   Emergency call to operator-   Manual message waiting-   Malicious Call Tracing-   External follow me-   Group Do Not Disturb-   Repeated Individual Diversion-   Personal Number-   Called/Calling/Connected number display-   Presentation restriction-   Name display-   Secretarial Supervision-   Saved number redial-   Message waiting-   Dial by Name-   Name and Number log-   Operator Call announcement-   Serial call-   Operator Camp-on-   Operator Intrusion-   Operator Supervision-   PABX operator supervised call charging-   Operator Identification of party connected to busy-   extension-   Night service-   Paging-   Call charging, individual and group-   Call information logging-   Music-on-hold-   Recorded Announcement-   Private Network Routing-   Least Cost Routing-   On-hook queuing-   Expensive Route Warning Tone-   DISA-   Toll Restrictions

1. A telephone exchange in a telecommunications network, the telephoneexchange comprising: means for registering a mobile telephone andassigning a unique extension identifier to the mobile telephone, whereinthe mobile telephone is adapted for communication with the telephoneexchange via a data channel and a voice channel through a mobiletelephony network; communication means for sending call setup signalingmessages to the mobile telephone and receiving call setup signalingmessages from the mobile telephone over the data channel; means forcontrolling interfaces associated with the mobile telephone using basictelephony and data communication services of the mobile telephonynetwork exclusive of special mobile operator agreements or specialinterfaces with the mobile telephony network; means for receiving overthe data channel, an indication that the mobile telephone is initiatinga call to a called number; and means for performing reverse directioncall setup in response to the indication that the mobile telephone isinitiating the call to the called number, said means for performingreverse direction call setup including: means for setting up a speechpath from the telephone exchange to the called number; means forinitiating an outgoing external call in a direction from the telephoneexchange to the mobile telephone; means for detecting that the mobiletelephone has answered the outgoing external call; and means forconnecting the speech path and the outgoing external call to form aspeech connection between the mobile telephone and the called number. 2.The telephone exchange of claim 1, wherein: a dedicated, direct speechconnection is set up between the telephone exchange and the mobiletelephony network via a public network trunk access interface; and aspeech channel is set up from the telephone exchange to the mobiledevice when a call is connected to the mobile telephone.
 3. Thetelephone exchange according to claim 1, further comprising means forproviding telephony services to the mobile telephone.
 4. The telephoneexchange according to claim 3, said means for providing telephonyservices further comprises providing the services without requiring anagreement with an operator of the mobile telephony network for thatpurpose.
 5. The telephone exchange according to claim 1, wherein thetelephone exchange stores information about the rights of users to useresources in the telephone exchange and information about user settingsand preferences, said information being selectable independent from theoperator of the mobile telephony network.
 6. The telephone exchangeaccording to claim 1, wherein the mobile telephone has an extensionidentity in the telephone exchange, said extension identity beingdifferent from the telephone number of said mobile telephone in themobile telephony network.
 7. The telephone exchange according to claim1, wherein the telephone exchange further comprises means to presentservice alternatives on the display of the mobile telephone, saidservice alternatives being relevant to the current state of theextension representing the mobile telephone, or relevant to the currentstate of a call on the extension.
 8. The telephone exchange according toclaim 1, wherein the telephone exchange further comprises means forallowing the user of the mobile telephone to select services of thetelephone exchange through in-band Dual-Tone Multi-Frequency (DTMF)signaling when the data channel is unavailable.
 9. The telephoneexchange according to claim 1, wherein the communication with the mobiletelephone passes over the data channel via a server that changes theformat of the communication to suit a browser in the mobile telephone.10. The telephone exchange according to claim 9, wherein the server is aWireless Application Protocol (WAP) server.
 11. A method in atelecommunications network of setting up a call from a mobile telephone,said method comprising the steps of receiving at a telephone exchange,an indication that a user of the mobile telephone desires to place thecall to a selected number, wherein the indication is received via a datachannel from the mobile telephone; performing reverse direction callsetup in response to the mobile telephone initiating the call to theselected number, said step of performing reverse direction call setupincluding: initiating an outgoing external call in a direction from thetelephone exchange to the mobile telephone to establish a first speechpath from the telephone exchange to the mobile telephone; setting up asecond speech path from the telephone exchange to the selected number;and connecting the first speech path and the second speech path tocomplete the call.
 12. A method in a telecommunications network ofselling up a call from a mobile telephone, said method comprising thesteps of: selecting a number to be called from a directory lookupservice; the mobile telephone signaling to a telephone exchange via adata channel of the mobile telephone, that a user of the mobiletelephone desires to place the call; transferring information associatedwith the selected number over the data channel of the mobile telephone;performing reverse direction call setup by the telephone exchange inresponse to the mobile telephone signaling call initiation, said step ofperforming reverse direction call setup including: initiating anoutgoing external call in a direction from the telephone exchange to themobile telephone to establish a first speech path from the telephoneexchange to the mobile telephone; setting up a second speech path fromthe telephone exchange to the selected number; and connecting the firstspeech path and the second speech path in the telephone exchange tocomplete the call.
 13. A method in a telecommunications network ofretrieving a voice message by a mobile telephone having a separate datachannel, said method comprising the steps of: sending from a telephoneexchange to the mobile telephone over the separate data channel,information that a voice message is available; receiving in thetelephone exchange, an indication from the mobile telephone that a userof the mobile telephone wants to listen to the voice message, saidindication being received over the separate data channel; and performingreverse direction call setup by initiating an outgoing external call ina direction from the telephone exchange to the mobile telephone toestablish a first speech path from the telephone exchange to the mobiletelephone in response to receiving the indication from the mobiletelephone that the user of the mobile telephone wants to listen to thevoice message.
 14. A method in a telecommunications network of sellingup a call from a mobile telephone to a number in a call log, the calllog being stored in a telephone exchange, comprising the steps of:sending to the mobile telephone, over a separate data channel of themobile telephone, information about the number in the log; receiving inthe telephone exchange, an indication from the mobile telephone that theuser of the mobile telephone has selected to call the number, saidindication being received over the separate data channel; and performingreverse direction call setup by the telephone exchange in response toreceiving the indication that the user of the mobile telephone hasselected to call the number, said step of performing reverse directioncall setup including: initiating an outgoing external call in adirection from the telephone exchange to the mobile telephone toestablish a first speech path from the telephone exchange to the mobiletelephone; selling up a second speech path from the telephone exchangeto the number in the call log; and connecting the first speech path andthe second speech path to form a speech connection between the mobiletelephone and the number in the call log.
 15. An arrangement in atelecommunications network comprising: a telephone exchange, comprising:means for registering a mobile telephone, wherein the mobile telephoneis adapted for communication with the telephone exchange via a datachannel and a voice channel; means for receiving over the data channel,an indication that a user of the mobile telephone desires to place acall to a called number; means for performing reverse direction callsetup in response to the indication that the mobile telephone isinitiating the call to the called number, said means for performingreverse direction call setup including: means for selling up a speechpath from the telephone exchange to the called number; means forinitiating an outgoing external call in a direction from the telephoneexchange to the mobile telephone; and means for connecting the speechpath and the outgoing external call to form a speech connection betweenthe mobile telephone and the called number; a mobile telephony networkfor providing a telephony service; a network that connects the telephoneexchange to the telephony service of the mobile telephony network; and adata network that connects the telephone exchange to the data channel ofthe mobile telephone through the mobile telephony network.
 16. Thearrangement according to claim 15, wherein the connection between thetelephone exchange and the telephony service of the mobile networkpasses via a public network trunk access interface.
 17. A method ofintegrating a mobile device, having mobile telephone functionality, asan extension of a telephone exchange, said method comprising the stepsof: registering a mobile telephone and assigning a unique extensionidentifier to the mobile phone, wherein the mobile telephone is adaptedfor communication with the telephone exchange via a data channel and avoice channel through a mobile telephony network; receiving signalingfrom the mobile telephone via the data channel indicating a user of themobile telephone desires to place a call; and performing reversedirection call setup by the telephone exchange in response to thesignaling from the mobile telephone, said step of performing reversedirection call setup including: initiating an outgoing external call ina direction from the telephone exchange to the mobile telephone inresponse to signaling from the mobile telephone initiating the outgoingcall; setting up a call from the telephone exchange to the desireddestination and connecting the outgoing call to the call to the desireddestination; controlling interfaces associated with the mobile telephoneusing basic telephony and data communication services of the mobiletelephony network exclusive of mobile operator agreements or specialinterfaces with the mobile telephony network; and setting up a speechchannel utilizing signaling from the mobile telephone via the datachannel.
 18. The method of claim 17, further comprising providingtelephony services to the mobile telephone.
 19. The method of claim 17,wherein the step of communicating with the mobile telephone via the datachannel further comprises delivering messages end to end regardless ofcontent.
 20. The method of claim 17, further comprising storinginformation about the rights of users to use resources in the telephoneexchange and information about user settings and preferences, saidinformation being selectable independent of the operator of the mobiletelephony network.
 21. The method of claim 17, wherein the mobiletelephone is assigned an extension identity in the telephone exchange,the extension identity being different from the telephone number of saidmobile telephone in the mobile telephony network.
 22. The method ofclaim 17, further comprising the step of presenting service alternativeson the display of the mobile telephone, said service alternatives beingrelevant to the current state of the extension representing the mobiletelephone, or relevant to the current state of a call on the extension.23. The method of claim 17, further comprising the step of allowing theuser of the mobile telephone to select telephony services from thetelephone exchange through in-band Dual-Tone Multi-Frequency (DTMF)signaling when the data channel is unavailable.
 24. The method of claim17, further comprising the step of communicating with the mobiletelephone via the data channel through a server that changes the formatof the communication to suit a browser in the mobile telephone.
 25. Themethod of claim 24, wherein the server is a Wireless ApplicationProtocol (WAP) server.
 26. The method of claim 12, wherein the directorylook up service is provided by a directory server associated with thetelephone exchange and the server is accessed through the data channelof the mobile telephone.
 27. The method of claim 12, further comprisingthe step of the mobile telephone selecting a call alternative enablingthe directory service to send a signal to the telephone exchange forsetting the speech path from the telephone exchange to the mobiletelephone.
 28. The method of claim 12, wherein communication takes placebetween the directory server and a browser in the mobile telephone usinga server adapted for: handling communication protocols; addingformatting and user interface details to messages; and converting theformat of exchanged messages.
 29. The method of claim 12, furthercomprising forming a dedicated, direct speech connection between thetelephone exchange and the mobile telephony network via a public networktrunk access interface and setting up a speech channel from thetelephone exchange to the mobile telephone when a call is connected tothe mobile telephone.
 30. A call setup unit in a telecommunicationsnetwork, the call setup unit comprising: means for registering a mobiletelephone, wherein the mobile telephone is adapted for communicationwith the call setup unit via a data channel and a voice channel througha mobile telephony network; means for receiving over the data channel,an indication that the mobile telephone desires to initiate a call to acalled number; and means for performing reverse direction call setup inresponse to the indication that the mobile telephone desires to initiatethe call to the called number, said means for performing reversedirection call setup including: means for setting up a speech path fromthe call setup unit to the called number; means for initiating anoutgoing external call in a direction from the call setup unit to themobile telephone; and means for connecting the speech path and theoutgoing external call to form a speech connection between the mobiletelephone and the called number.
 31. The telephone exchange of claim 1,wherein the communication means for sending call setup signalingmessages to the mobile telephone and receiving call setup signalingmessages from the mobile telephone over the data channel includes meansfor sending a message to the mobile telephone causing the mobiletelephone to answer the outgoing external call from the exchange.